Abstract: A current-perpendicular-to-the-plane magnetoresistive sensor structure includes at least an improved top shield structure and optionally also a similar bottom shield structure. The top shield structure includes an antiparallel structure (APS) of two ferromagnetic films and a nonmagnetic antiparallel coupling (APC) film between them. The APC film induces antiferromagnetic (AF) coupling between the two ferromagnetic films so that they have their respective magnetizations oriented antiparallel. An important aspect of the APS is that there is no antiferromagnetic layer adjacent the upper ferromagnetic film, so that the upper ferromagnetic film does not have its magnetization pinned by an antiferromagnetic layer. An electroplated shield layer is formed above the APS.

Abstract: A method for determining a magnetic anisotropy of a free layer of a magnetoresistive sensor. The method includes forming a functional magnetoresistive sensor and also a test sensor on a wafer. The test sensor has a sensor stack that is identical to that of the functional sensor, however the test head does not have a magnetic bias structure for biasing the free layer. A series of tests can be performed to construct a transfer curve for the test sensor. This can then be used to determine a magnetic anisotropy of the test head, which also corresponds to a magnetic anisotropy of the functional head.

Abstract: Embodiments of the invention provide methods, systems and apparatus for testing electronic components, and more specifically for testing magnetoresistive heads. A pair of top shield pads and a pair of bottom shield pads may be formed in a kerf region of a wafer on which magnetoresistive heads are formed. The top shield pads, bottom shield pads, and a magnetoresistive head may form a circuit that may be coupled with a testing circuit to exchange test signals configured to test the magnetic head. The pair of bottom shield pads may provide balanced impedance to substrate that nullifies the effects of broadband noise.

Abstract: A method for manufacturing a current perpendicular to plane magnetoresistive sensor that allows for dynamic adjustment of free layer biasing to compensate for variations in thickness of an electrically insulating layer that separates the hard bias layers from the free layer. During fabrication of the sensor, the actual thickness of the insulation layers is measured. Then, to maintain a desired magnetic stabilization of the free layer one of three options can be utilized. Option one; adjust the stripe height target to maintain the desired magnetic stabilization. Option two; adjust the hard magnet thickness to maintain the desired magnetic stabilization. Option three; use a combination of option one and option two, adjusting both the stripe height target and the hard magnet thickness to maintain the desired magnetic stabilization.

Abstract: A method for determining a magnetic anisotropy of a free layer of a magnetoresistive sensor. The method includes forming a functional magnetoresistive sensor and also a test sensor on a wafer. The test sensor has a sensor stack that is identical to that of the functional sensor, however the test head does not have a magnetic bias structure for biasing the free layer. A series of tests can be performed to construct a transfer curve for the test sensor. This can then be used to determine a magnetic anisotropy of the test head, which also corresponds to a magnetic anisotropy of the functional head.

Abstract: Built-in electrical test structures are measured for lead-to-lead shorting during the fabrication of MR elements on a wafer. The test structures are fabricated in the same fashion as the MR elements, however, the active sensor region or track width is omitted from the test structures. Thus, the left and right leads for each test structure are electrically isolated from each other in their “track width” region. If there is lead-to-lead shorting on a test structure, then the left and right leads are electrically connected in the track width region. A simple resistance measurement between the left and right leads determines the extent of any lead shorting by giving a quantitative resistance value.

Abstract: Embodiments of the invention provide methods, systems and apparatus for testing electronic components, and more specifically for testing magnetoresistive heads. A pair of top shield pads and a pair of bottom shield pads may be formed in a kerf region of a wafer on which magnetoresistive heads are formed. The top shield pads, bottom shield pads, and a magnetoresistive head may form a circuit that may be coupled with a testing circuit to exchange test signals configured to test the magnetic head. The pair of bottom shield pads may provide balanced impedance to substrate that nullifies the effects of broadband noise.

Abstract: A method for manufacturing a current perpendicular to plane magnetoresistive sensor that allows for dynamic adjustment of free layer biasing to compensate for variations in thickness of an electrically insulating layer that separates the hard bias layers from the free layer. During fabrication of the sensor, the actual thickness of the insulation layers is measured. Then, to maintain a desired magnetic stabilization of the free layer one of three options can be utilized. Option one; adjust the stripe height target to maintain the desired magnetic stabilization. Option two; adjust the hard magnet thickness to maintain the desired magnetic stabilization. Option three; use a combination of option one and option two, adjusting both the stripe height target and the hard magnet thickness to maintain the desired magnetic stabilization.

Abstract: Built-in electrical test structures are measured for lead-to-lead shorting during the fabrication of MR elements on a wafer. The test structures are fabricated in the same fashion as the MR elements, however, the active sensor region or track width is omitted from the test structures. Thus, the left and right leads for each test structure are electrically isolated from each other in their “track width” region. If there is lead-to-lead shorting on a test structure, then the left and right leads are electrically connected in the track width region. A simple resistance measurement between the left and right leads determines the extent of any lead shorting by giving a quantitative resistance value.

Abstract: In fabricating magnetic heads on a wafer surface, magnetoresistive sensors having two different stripe heights and the same stripe width are formed. Additionally, two different electronic lapping guides (ELGs) having different stripe heights and the same stripe width are also formed. While the design widths and heights of the sensors and ELGs are known, the actually fabricated widths and heights of the sensors and ELGs is unknown, due to the windage in the fabrication process. In the present invention, to determine the actual track width of the sensors, the change in electrical resistance of the sensors and ELGs is experimentally determined during the application of a magnetic field to the sensors and ELGs. Through a mathematical analysis, the actual track width of the fabricated sensors is determined utilizing the design widths and heights of the sensors and ELGs, together with the experimentally determined changes in electrical resistance of the sensors and ELGs.

Abstract: In fabricating magnetic heads on a wafer surface, magnetoresistive sensors having two different stripe heights and the same stripe width are formed. Additionally, two different electronic lapping guides (ELGs) having different stripe heights and the same stripe width are also formed. While the design widths and heights of the sensors and ELGs are known, the actually fabricated widths and heights of the sensors and ELGs is unknown, due to the windage in the fabrication process. In the present invention, to determine the actual track width of the sensors, the change in electrical resistance of the sensors and ELGs is experimentally determined during the application of a magnetic field to the sensors and ELGs. Through a mathematical analysis, the actual track width of the fabricated sensors is determined utilizing the design widths and heights of the sensors and ELGs, together with the experimentally determined changes in electrical resistance of the sensors and ELGs.